how to select a number from a line of file in c code example

Example: how to count lines in a file c

/* C Program to count the Number of Lines in a Text File  */
#include <stdio.h> 
#define MAX_FILE_NAME 100 
  
int main() 
{ 
    FILE *fp; 
    int count = 0;  // Line counter (result) 
    char filename[MAX_FILE_NAME]; 
    char c;  // To store a character read from file 
  
    // Get file name from user. The file should be 
    // either in current folder or complete path should be provided 
    printf("Enter file name: "); 
    scanf("%s", filename); 
  
    // Open the file 
    fp = fopen(filename, "r"); 
  
    // Check if file exists 
    if (fp == NULL) 
    { 
        printf("Could not open file %s", filename); 
        return 0; 
    } 
  
    // Extract characters from file and store in character c 
    for (c = getc(fp); c != EOF; c = getc(fp)) 
        if (c == '\n') // Increment count if this character is newline 
            count = count + 1; 
  
    // Close the file 
    fclose(fp); 
    printf("The file %s has %d lines\n ", filename, count); 
  
    return 0; 
}